Mass Balance of the Greenland and Antarctic Ice Sheets from 1992 to 2020
Inès Otosaka, Andrew Shepherd, Erik R. Ivins, Nicole‐Jeanne Schlegel, Charles Amory, M. R. van den Broeke, Martin Horwath, Ian Joughin, Michalea D. King, Gerhard Krinner, Sophie Nowicki, A. J. Payne, Eric Rignot, T. A. Scambos, Karen M. Simon, B. E. Smith, Louise Sandberg Sørensen, I. Velicogna, Pippa L. Whitehouse, A Geruo, Cécile Agosta, Andreas P. Ahlstrøm, Alejandro Blazquez, William Colgan, Marcus Engdahl, Xavier Fettweis, R. Forsberg, Hubert Gallée, Alex Gardner, Lin Gilbert, Noël Gourmelen, Andreas Groh, B. C. Gunter, Christopher Harig, Veit Helm, Shfaqat Abbas Khan, Hannes Konrad, Peter L. Langen, Benoit S. Lecavalier, Chia-Chun Liang, Bryant Loomis, Malcolm McMillan, Daniele Melini, Sebastian H. Mernild, Ruth Mottram, J. Mouginot, Johan Nilsson, Brice Noël, Mark E. Pattle, W. R. Peltier, Nadège Pie, Ingo Sasgen, Himanshu Save, Ki‐Weon Seo, B. Scheuchl, Ernst Schrama, Ludwig Schröder, Sebastian B. Simonsen, Thomas Slater, Giorgio Spada, Tyler Sutterley, Bramha Dutt Vishwakarma, Jan Melchior van Wessem, D. N. Wiese, Wouter van der Wal, Bert Wouters
Abstract
Abstract. Ice losses from the Greenland and Antarctic Ice Sheets have accelerated since the 1990s, accounting for a significant increase in global mean sea level. Here, we present a new 29-year record of ice sheet mass balance from 1992 to 2020 from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE). We compare and combine 50 independent estimates of ice sheet mass balance derived from satellite observations of temporal changes in ice sheet flow, in ice sheet volume and in Earth’s gravity field. Between 1992 and 2020, the ice sheets contributed 21.0 ± 1.9 mm to global mean sea-level, with the rate of mass loss rising from 105 Gt yr-1 between 1992 and 1996 to 372 Gt yr-1 between 2016 and 2020. In Greenland, the rate of mass loss is 169 ± 9 Gt yr-1 between 1992 and 2020 but there are large inter-annual variations in mass balance with mass loss ranging from 86 Gt yr-1 in 2017 to 444 Gt yr-1 in 2019 due to large variability in surface mass balance. In Antarctica, ice losses continue to be dominated by mass loss from West Antarctica (-82 ± 9 Gt yr-1) and to a lesser extent from the Antarctic Peninsula (-13 ± 5 Gt yr-1). East Antarctica remains close to a state of balance (3 ± 15 Gt yr-1), but is the most uncertain component of Antarctica’s mass balance.